Rotary tool guard

ABSTRACT

A rotary tool guard, and more particularly a shaper guard, including a disc-shaped guard member having a bearing member rotatably mounted upon the vertical spindle above the rotary tool for rotary movement independently of the tool. The rotary tool guard may also be provided with means for holding the guard member stationary, even while the spindle is rotating.

United States Patent Ulmer May 20, 1975 [5 ROTARY TOOL GUARD 1947,885 2/1934 Tautz 144/253 J 76 l t F.Ul ,Rt.l.H .70,Mt. 1 men or Wy Prtmary Examiner-Samuel Scott Assistant ExaminerF. D. Shoemaker [22] Filed: May 23, 1974 Attorney, Agent, or Firm-Harrington A. Lackey [21] App]. No.: 472,835

[57] ABSTRACT [52 us. (:1. 1. 74/609- 144/134 A' 144/251 A- A "nary guard and mm Particularly a Shape 144/253 guard, including a disc-shaped guard member having a 51 Int. Cl. .1 Fl6p 1/00 bearing member matably mmmed the [58] Field of Search- 4 5, 144/251 A 253 J spindle above the rotary tool for rotary movement in- 144/134 134 dependently of the tool.

The rotary tool guard may also be provided with [56] References Cited means for holding the guard member stationary, even UNITED STATES PATENTS while the spindle iS rotating.

955,482 4/1910 Stewart l44/251 A 11 Claims, 3 Drawing Figures ROTARY TooL GUARD BACKGROUND OF THE INVENTION This invention relates to a rotary tool guard, and more particularly to a shaper guard.

Heretofore, shaper guards have been of various designs, primarily ring-shaped, and mounted above the rotary shaper tool by a standard or bracket fixed to the shaper table at a laterally remote position from the shaper tool spindle.

The prior art shaper guards, because of their stationary position and stationary mounting, are oftentimes removed by the operator because the shaper guard, or its mounting bracket, gets in the operators way, or obscures the operators vision of his work. The removal of the shaper guard and its mounting bracket, of course, maximizes the danger of injury to the operator.

Such prior art shaper guards are clearly shown in U.S. Pat. No. 1,706,156 issued to Hall, Mar. 19, 1929, and US. Pat. No. 2,642,104 issued to Brown on June 16, 1953.

Cylindrical shaped guards for rotary cutter heads, which are fixed to the spindle above the cutter head are also known, as illustrated in US. Pat. No. 337,493, issued to Hall on Mar. 9, 1886.

Disc-shaped shaper guards, which are fixed to the spindle of the shaper tool and which are provided with openings through the guard for visibility, are disclosed in US Pat. No. 828,706, issued to Bohling, et al., on Aug. 14, 1906, and in US. Pat. No. 955,482 issued to Stewart on Apr. 19, 1910. The Stewart shaper guard is provided with a transparent celluloid material.

However, it is not believed that the prior art includes any disc-shaped guards which are mounted upon the tool spindle by bearings which permit rotation of the shaper guard independently of the spindle.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a rotary tool guard, and more particularly a shaper guard, which includes an annular body mounted upon the spindle of a rotary tool by bearings.

More specifically, a preferred form of shaper guard includes a solid annular body having an opening coaxially through the center thereof for fitting over the upper part of the spindle above the rotary tool. Within the central opening there is a bearing means or member including an outer race fixed to the inner portion of the guard member and an inner race adapted to be fixed to the spindle, with a bearing or bearings supported between the inner and the outer race to permit rotary independent movement of the guard relative to the spindle.

The purpose of having a bearing mounting for the guard upon the spindle is normally to permit the shaper guard to rotate, but at a slower speed than the very rapid angular velocity of the shaper spindle. For example, where the shaper spindle might be rotating at approximately 7,500 RPM, the shaper guard mounted upon the spindle by bearings might travel at approximately 3,500 RPM, which is sufficiently rapid to dis courage the operator from removing the guard from the spindle, yet not so rapid as to injure an operator who night inadvertently come in contact with the rapidly spinning shaper guard. The reason that the shaper guard rotates at all, is of course, because of the friction between the outer race, bearing members and inner race which tend to drag the shaper guard in' the same rotary direction as the driven spindle.

In some cases, where it is desired that the guard member not rotate at all, then the guard member may be held stationary by any appropriate means such as a stop element engaging the rim of the guard, or a locking pin extending through mating apertures in the guard and the stationary platform below the guard. When the guard member is held stationary, the bearing members still permit the rapid rotation of the spindle and the shaper tool.

Also, in a preferred form of the invention, the discshaped guard member has its annular major body portion continuously transparent to permit constant visibility of the work beneath the guard by the operator, regardless of the position of the guard.

Another object of this invention is to provide a shaper guard which has no mounting portions or brackets projecting laterally beyond the periphery of the guard itself.

Also in a preferred form of the invention, the rim of the disc-shaped guard member is surrounded and completely covered by a soft resilient material, such as rubber or polyurethane. I

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top perspective view of the guard, made in accordance with this invention, mounted upon the spindle of a shaper tool, with portions of the shaper table and fence shown fragmentarily;

FIG. 2 is an enlarged, fragmentary, section taken along the line 22 of FIG. 1; and

FIG. 3 is a fragmentary section taken along the line 33 of FIG. 1, with a portion of the guard in section.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings in more detail, the shaper machine 10 includes a table 11, shown fragmentarily and a pair of opposed fence elements 12 and 13 adapted to be longitudinally adjusted toward and away from each other. The fence elements 12 and 13 may be locked in adjusted positions against the rigid brackets 14 by the threaded clamping elements 15.

Projecting upward through an opening 17 in the table 11 is a vertical spindle 18 which is rotatably driven about its vertical axis by a motor and transmission, not

shown, within the machine 10 and below the table 11. Fixed upon the spindle 14 is a shaper tool 20 having blades 21 of the desired configuration for forming or shaping a wooden piece of work fed over the top of the table 11 for cutting engagement with the shaper blades 21. The fence elements 12 and 13, of course, are employed to guide the work as it is shaped.

The shaper blades 21 are fixed upon the lower portion of the upper section 22 of the spindle 18, the upper section 22 being that part of the spindle 18 which projects above the hole 17 in the table 11. The upper spindle section 22 is adapted to project above the shaper blades 21, and is also preferably threaded, as shown.

The rotary tool guard or shaper guard 25 is discshaped and provided with a hole or opening 26 in the center thereof to fit over the upper spindle section 22.

The tool guard or guard member 25 is mounted upon the upper spindle section 22 by a bearing member 27, including an annular outer race 28 fixed to the guard member 25 against the opening 26, and an annular inner race 29 having an internally threaded opening adapted to threadedly engage the upper spindle section 22. In operative engagement between the outer race 28 and the inner race 29 are one or more bearings, such as the plurality of ball bearings 30, permitting independent rotation of the outer race 28 and the inner race 29. Accordingly, the shaper guard or guard member 25 is rotatable independently of the spindle 18.

The major portion of the guard member 25 is an annular body portion 32, preferably solid, and also preferably of transparent material, such as a transparent acrylic resin, for example Plexiglass.

A groove 33 is formed circumferentially around the periphery of the annular body portion 32 to receive the annular rib 34 of the annular rim 35 of the guard member 25. The annular rim 35 is made of a soft resilient material, such as rubber or polyurethane, for protection of the operator against accidental contact with the periphery of the guard member 25, while it is rotating.

The bottom surface of the inner race 29 is separated from the shaper tool by a washer or spacer 37 around the spindle section 22. The spacer 37 also provides a surface against which the inner race 29 is forced and held in clamped position by a nut member 38. The nut member 38 threadedly engages the upper spindle section 22 and is tightened down upon an upper spacer 39, which forces the inner race 29 against the spacer 37. It will be noted in FIG. 2 that the upper and lower spacers 39 and 37 are of slightly lesser diameter than the inner race 29, so as not to interfere with the independent rotation of the body member 32. A guard washer 40, having a larger diameter than the hole 26, is coaxially fitted upon the spindle section 22 between the nut 38 and the upper spacer 39 to prevent the body portion 32 from accidentally flying off the outer race 28.

The guard member may be vertically adjusted upon the upper spindle section 22 by rotating the inner race in threaded engagement with the upper spindle section 22, and by inserting spacers 37 of different thicknesses.

As the spindle 18 is driven, the shaper tool 20, as well as the inner race 29, rotates at the same speed as the driven spindle 18, by virtue of these parts being fixed to the spindle 18. Because of the frictional engagement between the ball bearings and the respective inner race 29 and outer race 28, the shaper guard member 25 will also be dragged along in the same rotary direction of the spindle 18, but at a much reduced speed, depending upon the degree of friction between the ball bearings 30 and the inner race 29 and outer race 28. Even so, the annular velocity of the shaper guard 25, even though less than the high annular velocity of the spindle 18, will still be sufficiently great to discourage an operator from voluntarily touching or grasping the shaper guard member 25. Should the operator accidentally touch or engage the shaper guard 25 he will not be injured or chafed nearly as greatly, if at all, as he would be if the guard member 25 were fixed to the rapidly rotating spindle 18. Moreover, contact of the shaper guard member 25 by the operator will cause immediate reduction in speed of the shaper guard member 25 because of its floating connection through the bearings 30 with the spindle 18.

Furthermore, injury to the operator is further avoided by the resilient material in the rim disposed continuously around the periphery of the guard member 25.

If the body portion 32 is transparent, the operator will still have maximum visibility through the continuously transparent body portion 32, even though the guard member 25 rotates rapidly and continuously. Since the transparent body portion 32 is completely annular and of uniform radial dimensions, visibility through the guard member 25 is uniform and continuous regardless of the rotational position or rotational speed of the guard member 25.

Where it is desired to hold the guard member 25 stationary, the threaded clamping elements 15 may be loosened, while the shaper guard member 25 is rotating, and one or the other, or both, of the fence elements 12 and 13 may be urged radially inward to engage the periphery of the rim 35. Moreover, the fence elements 12 and 13 may be urged inwardly into engagement with the rim 35, even before rotation of the spindle 18 is begun.

An optional means for holding the shaper member 25 stationary is the locking pin 45 which may be urged downward through an opening 46 of corresponding size, completely vertically through the thickness of the annular body portion 32, and down into a mating aperture 47 through the table 1 1, as best disclosed in FIGS. 1 and 3.

Where an operator is of a disposition, or mature enough, not to desire to remove the guard member 25 from the spindle 18, then it may be preferable to hold the guard member 25 in a stationary position to minimize any possibility of injury to the operator by the rotating guard member 25.

What is claimed is:

1. A guard for a rotary tool apparatus having a platform, a vertical spindle projecting above said platform and rotatably driven about its vertical axis, and a rotary tool fixed to the portion of the spindle adjacent and above said platform for operating upon work upon said platform in engagement with said tool, comprising:

a. a disc-shaped guard member having a diameter greater than the maximum diameter of the swath of said rotary tool, and

b. bearing means rotatably mounting said guard member coaxially upon said spindle above said rotary tool, whereby said guard member may rotate independently of said spindle.

2. The invention according to claim 1 in which said guard member has an opening through the center thereof, said bearing means comprising an outer race fixed to said guard member coaxially within said opening, said bearing means further comprising an inner race within said outer race and means fixing said inner race to said spindle, and at least one bearing member between said inner and outer races to permit independent rotation between said inner and outer races.

3. The invention according to claim 2 in which the said means for fixing said inner race to said spindle comprises cooperating threads in opposed surfaces of said inner race and said spindle.

4. The invention according to claim 3 further comprising nut means threadedly secured to the threaded portion of said spindle in various vertically adjusted po sitions on said spindle.

5. The invention according to claim 4 further comprising a spacer member mounted on said spindle between said inner race and said rotary tool.

6. The invention according to claim 2 in which said guard member has a major annular body portion between said opening and the rim of said guard member of solid material.

7. The invention according to claim 6 in which said solid material is transparent.

8. The invention according to claim 6 in which said rim is made of soft resilient material surrounding the periphery of said annular body portion. 9. The invention according to claim 1 further comprising means for selectively engaging said guard member and holding said guard member stationary, even while said spindle is rotating.

10. The invention according to claim 9 in which said form when said openings are in vertical alignment. 

1. A guard for a rotary tool apparatus having a platform, a vertical spindle projecting above said platform and rotatably driven about its vertical axis, and a rotary tool fixed to the portion of the spindle adjacent and above said platform for operating upon work upon said platform in engagement with said tool, comprising: a. a disc-shaped guard member having a diameter greater than the maximum diameter of the swath of said rotary tool, and b. bearing means rotatably mounting said guard member coaxially upon said spindle above said rotary tool, whereby said guard member may rotate independently of said spindle.
 2. The invention according to claim 1 in which said guard member has an opening through the center thereof, said bearing means comprising an outer race fixed to said guard member coaxially within said opening, said bearing means further comprising an inner race within said outer race and means fixing said inner race to said spindle, and at least one bearing member between said inner and outer races to permit independent rotation between said inner and outer races.
 3. The invention according to claim 2 in which the said means for fixing said inner race to said spindle comprises cooperating threads in opposed surfaces of said inner race and said spindle.
 4. The invention according to claim 3 further comprising nut means threadedly secured to the threaded portion of said spindle in various vertically adjusted positions on said spindle.
 5. The invention according to claim 4 further comprising a spacer member mounted on said spindle between said inner race and said rotary tool.
 6. The invention according to claim 2 in which said guard member has a major annular body portion between said opening and the rim of said guard member of solid material.
 7. The invention according to claim 6 in which said solid material is transparent.
 8. The invention according to claim 6 in which said rim is made of soft resilient material surrounding the periphery of said annular body portion.
 9. The invention according to claim 1 further comprising means for selectively engaging said guard member and holding said guard member stationary, even while said spindle is rotating.
 10. The invention according to claim 9 in which said holding means comprises a stopping element mounted on said platform outside said rim and adapted to be reciprocably moved toward and away from engagement with said rim diametrically of said disc-shaped guard member.
 11. The invention according to claim 9 in which said holding means comprises an opening through the thickness of said guard member and a corresponding opening in said platform, and further comprising a locking pin adapted to fit through the opening in said guard member and to be received in the opening in said platform when said openings are in vertical alignment. 